Machine-to-Machine Communication (M2M Communication, Machine Type Communication (MTC))
In the following description, a machine-to-machine communication (M2M communication, machine type communication (MTC)) is briefly explained.
A machine-to-machine (hereinafter abbreviated M2M) communication literally means a communication between one electronic device and another electronic device. In particular, the M2M communication means a communication between objects. In general, the M2M communication may mean a wire/wireless communication between electronic devices or a communication between a human-controllable device and a machine. Yet, the M2M communication may specifically indicate a communication between electronic devices, i.e., a device-to-device wireless communication. And, M2M user equipments used in a cellular network are inferior to general user equipments in terms of performance or capability.
A plurality of user equipments may exist within a cell and a plurality of the user equipments can be classified into each other according to a type, a class, a service type and the like of a user equipment.
As an example, a user equipment can be mainly classified into a user equipment for a HTC (human type communication) and a user equipment for a MTC (machine type communication). The MTC may include a communication between M2M user equipments. In this case, the HTC means that a signal transmission is determined by a human and a signal is transmitted and received by a human. On the contrary, the MTC means that each of a plurality of the user equipments transmits a signal on an event occurrence or periodically without human involvement.
And, if a machine-to-machine communication (M2M communication or a machine type communication (MTC)) is considered, the total number of user equipments may rapidly increase. M2M user equipments may have attributes described in the following depending on services supported by the user equipments.
1. a plurality of user equipments within a cell
2. small amount of data quantity
3. low transmission frequency (may have periodicity)
4. data attribute of a limited number
5. not sensitive to time delay
6. may have low mobility or no mobility
And, the M2M communication can be used for such various fields as secured access and surveillance, tracking and tracing, public safety (emergency, disaster), payment (vending machine, ticket machine, and parking meter), healthcare, remote controlling, smart meter, and the like.
Idle Mode
An idle mode is a mechanism for enabling a user equipment to periodically receive a downlink broadcast message without registering a specific base station although the user equipment wanders around a radio link environment at which a plurality of base stations are located over regions of a wide range.
The idle mode terminates all normal operations as well as a handover (hereinafter abbreviated HO). The idle mode corresponds to a state with which downlink synchronization is matched only to receive a paging message, which is a broadcast message, in a prescribed interval only. The paging message is a message for indicating the user equipment to perform a paging action. For instance, the paging action may include a ranging performance, a network reentry, and the like.
The idle mode may be initiated by a user equipment or a base station. In particular, the user equipment can enter into the idle mode in a manner of transmitting a de-registration request (DREG-REQ) message to the base station and receiving a de-registration response (DREG-RSP) message from the base station in response to the de-registration request (DREG-REQ) message. And, the base station can enter into the idle mode in a manner of transmitting a non-request de-registration response (DREG-RSP) message or a de-registration command (DREG-CMD) message to the user equipment.
If the user equipment receives a paging message corresponding to the user equipment for an available interval (AI) in the idle mode, the user equipment switches to a connected mode by performing a network entry process with the base station and then transceives data with the base station.